The worm has infected tens of thousands of web sites, according to the US Computer Emergency Response Team.

And while estimates of a loss of around $1.2bn (£838m) surfaced early on Wednesday, those estimates are destined to rise as the worm gains ground.

The US National Infrastructure Protection Centre (NIPC) said in a statement the worm's potential is unknown, and it will provide updates throughout the day.

NIPC spokeswoman Deborah Weierman would not speculate on the costs associated with the worm's spread, saying it may take days or a week to calculate the damage figure.

"The figures that we would have first off would be the number of infected systems," Ms Weierman said. "We would not get into dollar loss for quite some time yet."

She added the NIPC has seen infections worldwide and her agency is concerned with computer systems everywhere.

Hundreds of users line up to pay $1 for access to the internet

The Code Red Worm was supposed to upset use of the internet for 19 days. But that level of devastation has yet to materialise.

Expensive virus

Nevertheless, businesses around the world have are spending big bucks servicing damaged networks, according to Michael Erbschloe, vice president of research at California-based Computer Economics.

"Information technology people are not cheap," he said.

"A lot of companies have outsourced this and they to pay sometimes $300 an hour to have people come in and look at their servers."

Costs such as that might leave proprietors of internet cafés quaking in their boots. But EasyEverything founder Stelios Haji-Ioannou has taken it all in stride.

EasyEverthing, which bills itself as the world's largest internet cafés, operates 20 stores in Europe and one shop in the US - in New York's Time Square district.

"Consumers expect a certain degree of unreliability"

"We've applied the patch Microsoft has recommended," Mr Haji-Ionnou told the BBC, adding he thought his stores were safe from the worm but customers might be affected if their email providers had not applied the patch.

Mr Haji-Ionnou, whose other ventures include EasyJet, a discount airline, and EasyRentacar, would not speculate on who might be behind the worm virus.

But he said he was not surprised that someone would attempt to create such a sophisticated programme to disrupt the internet.

Some of EasyEverything's users try to find ways to get free internet access, he said, in order to save the $1 fee he charges.

"If people are willing to work for that objective, how much more effort are they willing to put into the system as a whole?" he said, adding that his business has got to live with computer hackers just in the same way society has to live with any other criminal activity.

Business as usual

Business at the Big Apple location was bustling mid-afternoon on Tuesday when BBC News Online visited to see how the threat of the Big Red virus might be affecting business.

Thirty-two thousand people a week pile into the Times Square store to use the facility's 800 terminals - nearly twice the size of average European locations.

Mr Haji-Ionnou does not believe that any interruption in internet service at any of his location would cause mass consternation on the part of his patrons.

People expect a certain degree of unreliability when it comes to technology and to the internet, he says.